IAP-25-141

Light for Life: Optical Sensing Platforms for Environmental Water Quality Monitoring

This project aims to develop and apply advanced fiber-optic sensing technologies for real-time monitoring of water quality in the rivers and estuaries of Northeast UK and elsewhere. By designing and deploying etched and tilted fiber Bragg grating (FBG) sensors, the research will generate high-resolution data on pollutants such as heavy metals, nutrients, and microbial indicators, offering new insights into pollutant dynamics and ecosystem responses.

Using advanced experimental physics techniques in optics, and nanomaterials, the project will explore how light–matter interactions in optical fibers can be engineered for selective detection of environmental contaminants. This interdisciplinary approach combines laboratory-based sensor innovation with in-situ environmental monitoring, bridging fundamental physics, hydrodynamic modelling and applied environmental science.

The research is supported by a supervisory team with complementary expertise: Dr. Vasu Kalangi (Newcastle University) in physics, optics, and nanomaterials; Dr. Cathal Cummins (Heriot-Watt University) in hydrodynamics; and Prof. Peter Hunter (University of Stirling) in field-scale sensing and environmental systems. Together, they will ensure the project delivers both scientific advances and practical environmental impact, directly aligned with NERC’s priorities in Water quality monitoring, Environmental pollutant detection, Sustainable freshwater ecosystem management, and Tools, technology and methods.

Sensor Development (PhD Student + Dr Kalangi):[a] Fabrication: Develop etched and tilted FBG sensors optimized for environmental sensing. This includes micro-structuring of the FBGs to enhance evanescent field interaction and spectral sensitivity.[b] Functionalization: Apply selective nanomaterials coatings such as metal nanoparticles, two-dimensional materials and functional groups to enable detection of target analytes such as heavy metals (Pb²⁺, Cd²⁺), nutrients (NO₃⁻, PO₄³⁻), and microbial contaminants (E. coli).[c] Calibration: Perform laboratory-based calibration under controlled chemical and temperature conditions to establish the relationship between spectral shifts and analyte concentrations.

Field Deployment (PhD Student + Dr Kalangi + Prof Hunter):[a] Site Selection: Work with regional environmental partners and existing catchment observatories (e.g., the Forth-ERA network and Newcastle University Stronger Shores initiative) to identify representative riverine and estuarine sites in the UK.[b] Installation: Integrate FBG sensors into existing water monitoring platforms. Prof Hunter will provide guidance on deployment strategies, flow modelling, and data integration within multi-sensor networks.[c] Monitoring: Conduct long-term monitoring campaigns to evaluate sensor robustness, stability, and environmental response.

Data Analysis and Modelling (PhD Student + Dr Kalangi + Dr Cummins):[a] Signal Processing: Analyse the reflection and transmission spectra of FBGs to quantify analyte-induced shifts, using computational signal analysis and noise correction algorithms.[b] Hydrodynamic Modelling: Apply hydrodynamic simulations (under guidance of Dr Cummins) to interpret sensor response in the context of flow conditions, boundary layer effects, and pollutant dispersion.[c] Data Integration: Combine optical and hydrodynamic data to build predictive models linking physical, chemical, and biological parameters to observed optical signatures.

Future Directions:
In later stages, the project will explore integration of FBGs into on-chip photonic devices to enable multiplexed and miniaturized sensing architectures, paving the way for next-generation, portable water-quality sensors.

Year 1

The first year will focus on developing the student’s experimental and analytical skills while establishing the fundamental sensor platform.
Q1–Q2: Fabrication of etched and tilted FBG sensors; optimization of etching parameters and microstructural design for enhanced sensitivity.
Q2–Q3: Laboratory testing of baseline sensor performance under controlled temperature and salinity conditions.
Q3–Q4: Functionalization of sensors with selective nanomaterials coatings for heavy metals and nutrients; calibration experiments to quantify spectral shifts against known analyte concentrations.
End of Year 1 Deliverable: Demonstration of reproducible, laboratory-calibrated sensors capable of detecting key target pollutants under controlled conditions.

Year 2

The second year will consolidate sensor development through field deployment and modelling integration.
Q1–Q2: Site selection in collaboration with local environmental monitoring groups and Prof. Hunter’s team; preparation of deployment infrastructure.
Q2–Q3: Installation of sensors in selected freshwater and estuarine sites; initiation of real-time data acquisition campaigns.
Q3–Q4: Parallel hydrodynamic simulations to interpret fluid–fiber interactions and pollutant transport in collaboration with Dr. Cummin’s team; analysis of initial field data to assess sensor stability and environmental response.
End of Year 2 Deliverable: Operational deployment of FBG sensors with validated data streams and preliminary hydrodynamic models linking flow conditions to optical response.

Year 3

The third year will focus on refining data interpretation, expanding field studies, and integrating the sensing results into broader environmental frameworks.
Q1–Q2: Continued field monitoring across seasonal cycles to assess long-term sensor stability and calibration drift.
Q2–Q3: Refinement of data-processing algorithms and hydrodynamic models; correlation of FBG data with environmental parameters such as salinity, nutrient levels, and microbial activity.
Q3–Q4: Synthesis of results for publication; integration of findings into broader environmental sensing strategies in consultation with the supervisory team and collaborators.
End of Year 3 Deliverable: A validated FBG-based sensing framework capable of providing reliable, high-resolution data for environmental water monitoring.

Year 3.5

The final six months will focus on dissemination and completion of the PhD.
Q1: Final validation of sensor performance and data-model integration.
Q1–Q2: Preparation of thesis chapters, manuscripts for peer-reviewed journals, and conference presentations.
End of Project Deliverables: Submission of PhD thesis and at least one major journal publication on FBG-based environmental sensing, demonstrating a successful proof-of-concept system ready for wider application.

The student will receive interdisciplinary training spanning physics, engineering, and environmental science. Key skill areas include:

[a] Sensor Fabrication: Micro-structuring, etching, and coating techniques for optical fibers.[b] Optical Sensing: Principles of optical and photonic sensing and signal analysis for environmental monitoring.[c] Surface Chemistry: Functionalization methods for analyte selectivity.[d] Hydrodynamic and Environmental Modelling: Linking sensor data to flow and pollutant transport processes (in collaboration with Prof Hunter).[e] Field Deployment: Experience in sensor installation, calibration, and maintenance under real environmental conditions.[f] Data Analysis: Training in computational modelling, spectral analysis, and environmental data integration.[g] Professional Development: Presentation and communication skills, academic writing, interdisciplinary teamwork, and stakeholder engagement.

Through this training, the student will gain deep expertise in experimental optics and photonics and environmental sensing, positioning them for careers across academia, environmental monitoring, and applied research sectors.